Dr. Acitelli studies sleep and sleep disorders. She is curious as to whether falling asleep in front of a television set causes people to fall asleep more slowly than falling asleep without watching TV. She recruits a sample of 60 middle-aged women from a local church who reported no history of sleep problems. She creates three conditions. All participants come to the sleep lab for three nights in a row and experience all three conditions. In the first condition (A), participants fall asleep in front of a television that is off. In the second condition (B), participants fall asleep in front of a television that is turned on to the same 24-hour news channel. In the third condition (C), participants fall asleep in front of a television that is turned on to the same 24-hour news channel but is muted. With the use of an electroencephalograph (EEG), the researcher measures how long it takes participants to fall asleep.
Given that Dr. Acitelli's participants have agreed to participate for three nights each, which technique should she use to minimize order effects?
a. Masking
b. Snowball sampling
c. Matched-groups design
d. Counterbalancing
